President Donald Trump on Monday warned Rep. Maxine Waters to “be careful what you wish for,” two days after the California congresswoman urged supporters to harass members of the Trump administration in public places.

Referring to Ms. Waters as an “extraordinarily low IQ person,” Mr. Trump tweeted Monday: “She has just called for harm to supporters, of which there are many, of the Make America Great Again movement.” He added: “Be careful what you wish for Max!”

At an event in Los Angeles Saturday, Ms. Waters sought to rally the crowd against Trump administration officials. “If you see anybody from that cabinet in a restaurant, in a department store, at a gasoline station, you get out and you create a crowd,” she said. “And you push back on them. And you tell them they’re not welcome anymore, anywhere.”

Congresswoman Maxine Waters, an extraordinarily low IQ person, has become, together with Nancy Pelosi, the Face of the Democrat Party. She has just called for harm to supporters, of which there are many, of the Make America Great Again movement. Be careful what you wish for Max!

On Friday night, White House press secretary Sarah Sanders was asked by the owner of the Red Hen restaurant in Lexington, Va., to leave. Tweeting about the incident Saturday, Ms. Sanders said she was asked to leave “because I work for @POTUS” and that she “politely left.”

“Her actions say far more about her than about me,” she added. “I always do my best to treat people, including those I disagree with, respectfully and will continue to do so.” She also addressed the matter at Monday’s press briefing, saying: “We are allowed to disagree, but we should be able to do so freely and without fear of harm.”

Mr. Trump defended his press secretary on Monday, calling her a “fine person.”

Last week, protesters chanted “Shame!” at Homeland Security Secretary Kirstjen Nielsen while she was dining at a Mexican restaurant, hours after she defended the White House’s zero-tolerance policy that resulted in the separation of thousands of immigrant children from their families at a briefing with reporters.